1. Field of the Invention
The present invention relates to an ultrasonic diagnosis apparatus, an image processing apparatus and an ultrasonic image taking method capable of presenting fine structures of a fine circulating blood stream at a capillary level and a blood vessel stream which is comparatively faster than that of a capillary in an imaging echo method executed by using an ultrasonic contrast medium as diagnosis information.
2. Description of the Related Art
According to an ultrasonic diagnosis, beat of the heart or a moving behavior of the embryo is provided by a real time display by a simple operation of only touching an ultrasonic probe from the body surface, inspection can be carried out repeatedly since the safety is high and a scale of a system is smaller than that of other diagnosis apparatus of X-ray, CT, MRI or the like and inspection can also be executed easily by moving to a bed side, which is convenient.
Further, although an ultrasonic diagnosis apparatus differs variously depending on kinds of functions provided thereto, a small-sized apparatus being able to carried by one hand has been developed and can be used at a maternity clinic or in a medical treatment at home without being influenced by exposure as in X-ray or the like in the ultrasonic diagnosis.
In recent years, an intravenous administration type ultrasonic contrast medium has been produced and an imaging echo method has been carried out. It is an object of the method to evaluate a dynamic flow behavior by intensifying a blood stream signal by is injecting an ultrasonic contrast medium from the vein in inspecting, for example, the heart or the lever. In a number of ultrasonic contrast media, micro bubbles function as a reflection source. In view of a property of a delicate member of bubble, even by ultrasonic irradiation at a normal diagnosis level, bubbles are suppressed by mechanical operation thereof, as a result, a signal intensity from a scanning face is reduced. Therefore, in order to observe a dynamic behavior of a circulating flow in real time, it is necessary to comparatively reduce collapse of bubbles by scanning such that imaging is carried out by ultrasonic transmission at a low sound pressure. Such an imaging by ultrasonic transmission at the low sound pressure also reduces a signal/noise ratio (S/N ratio) and therefore, there have been devised various signal processing methods to supplement therefor.
Further, the following method has been devised in, for example, JP-A-11-155858 by making full use of the above-described collapsing characteristic of bubbles of contrast media. That is, this is a method of A observing a dynamic behavior of bubbles filling a scanning section under irradiation at a low sound pressure, B suppressing bubbles in the section (strictly, in an irradiated volume) by switching the irradiated sound pressure to a high sound pressure, and C observing a behavior of bubbles flowing again into the section. The method is referred to as a replenishment method.
Meanwhile, generally, although when the blood vessel constructed in the organ of the living body is comparatively bold, a structure thereof is easy to grasp, in the case of illustrating even the finer branch by imaging echo, an image of complicatedly entwining the blood vessels is illustrated. Since the current ultrasonic contrast media are of a low invasive intravenous administration type, the media circulate the whole body. Therefore, it has been conceived in the ultrasonic diagnosis that an image as in selective image of the blood vessel in X-ray using a catheter cannot be provided.
However, it seems that bubbles can selectively be made to disappear by utilizing the above-described property of bubbles. Further, it is clinically much significant to be able to provide a diagnosis image as in imaging by X-ray in an ultrasonic image diagnosis by establishing such a method.